Components having high heat flux densities, for example 60 W/cm2, are used today especially in computers. Heat from these components must first be transferred into a liquid circulation system, and from there it is discharged to the ambient air via a liquid-air heat exchanger. The dissipation of heat from components having a high heat flux density is accomplished by means of heat absorbers or so-called “cold plates.” In these, heat is transferred to a cooling liquid, and the latter usually is caused to circulate in forced fashion in a circulation system.
In this context, the cooling liquid flows not only through the heat exchanger but also through a liquid pump, which produces the forced circulation and produces an appropriate pressure buildup and an appropriate volumetric flow rate through the heat absorber and an associated heat exchanger, so that the pertinent heat transfer coefficients become high, and the temperature gradients necessary for heat transfer become low.
A fan is usually arranged at the heat exchanger and produces, on the air side of the heat exchanger, forced convection of the cooling air and good transfer coefficients.